as a plan for the fullness of time, to unite all things in Him, things in heaven and things on earth. (Ephesians 1:10, ESV)
Today’s big question: what is God’s plan for heaven and earth?
God’s plan for the salvation of man started in the Garden and culminated when God sent His Son (Galatians 4:4–5; John 3:16), as Jesus Christ is central to carrying out His plan. This plan has yet to be completely fulfilled—one of the things that will happen at the completion of God’s plan is “to unite all things in Him, things in heaven and things on earth.”
This part of God’s plan will not happen while the earth remains cursed as a result of man’s sin (Isaiah 24:6; Genesis 3:17–18). The heavens and earth will be burned up with fire (2 Peter 3:7, 10). And that is why God’s plan also includes new heavens and a new earth, as 2 Peter 2:13 states below:
Nevertheless we, according to His promise, look for new heavens and a new earth in which righteousness dwells.
At the beginning, everything was perfect and at peace (Deuteronomy 32:4; Genesis 1:31; Colossians 1:15–19), but things have certainly changed since then. The word “unite” in Ephesians 1:10 can actually mean “re-unite” in the Greek, which actually makes good sense in the context. Just as the angels and man were created at the beginning by God and united in His perfect creation, all things will again be united in Christ. Furthermore, the earth was perfect before the Curse, and it will be perfect again—“and there shall be no more curse” (Revelation 22:3).
Because of Christ’s work, there will be a re-uniting effect with God, man, and His creation (including the new heavens and new earth), and there will be a full restoration of peace in Christ. Even in regard to God’s plan for the new heavens and new earth, Scripture consistently has Christ and His work on the Cross being central to the plan.
Have you ever wondered what the Garden of Eden looked like? Well, the new heavens and new earth will give us a “taste” in the future. http://www.answersingenesis.org/articles/2010/08/11/gods-plan-heaven-earth